N mineralization

Soil Health

Biological

Summary

Organic nitrogen mineralization involves the microbial conversion of organic nitrogen into mineral forms, primarily ammonium (NH4+) and nitrate (NO3-), by a diverse array of soil microorganisms. This process reflects the turnover of organic material in the soil and the availability of indigenous nitrogen pools to plants (Neiendam Nielsen & Winding, 2002). It is significant for ecosystem services such as water quality, plant production, and climate control (Lehmann et al., 2020).

Monitoring nitrogen mineralization provides valuable insights into the soil’s capacity to supply nitrogen to plants, playing a crucial role in assessing soil fertility and overall nutrient cycling (Bünemann et al., 2018).

Methodology summary

To measure N-mineralization soil samples must be sent to a laboratory.

N-mineralization is measured by the accumulation of NH4 + in soil slurry under aerobic conditions over a period of several weeks. Anaerobic incubation is sometimes preferred because there is less microbial immobilisation under anaerobic conditions and nitrification is inhibited (Nielsen et al., 2002).

Systematic sampling ensures that the entire site being sampled is well represented by the individual samples.
The analytical variability between laboratories can be controlled by analysing all samples by one specific method within one specific laboratory as done in the Dutch Soil Monitoring Programme (Nielsen et al., 2002).

To collect samples for sending to a laboratory, detailed information on soil sampling such as where to take the samples from, how many, the best time to sample, and depth of sampling can be found at the Farm Carbon Toolkit.

Metric threshold or direction of change

Not applicable

Agricultural
Forest
Grassland
Peatland
Saltmarsh
Wetland

Scale

Community

Cost

Medium

Tier

Tier 2

Technical expertise

High